Former head of the Defence Force Lieutenant General Jerry Mateparae has been appointed New Zealand's next Governor-General.

Sir Anand Satyanand ends his term as Governor-General in August.

Lt Gen Mateparae's appointment has been approved by the Queen and he will be sworn in on August 17, beginning a five-year term as New Zealand's 20th Governor-General.

Lt Gen Mateparae told reporters he was honoured to be asked to accept the role.

"When the Prime Minster asked me to meet with him a few weeks ago, I thought he wanted to discuss with me my arrival at the GCSB. You cannot imagine my surprise when he asked me to be the next Governor-General.

"I did need a few days to think it over and discuss it with [his wife] Janine."

Lt Gen Mateparae said the more he thought about the role, the more he thought he could contribute, especially "the notion of service for others, the drive for excellence and harnessing the strength in young New Zealanders".

"I have an unshakeable belief in New Zealanders."

He said his family - his wife and five children, including two teenage boys - would play a key role when he takes up the position at the end of August.

"As most parents of teenage boys will know, the boys will keep me well and truly grounded."

Mr Key told media Lt Gen Mateparae was the Government's first choice and he was pleased he "took up the offer".

Mr Key said he had decided Lt Gen Mateparae should be offered the role about six weeks ago and had consulted with Labour leader Phil Goff, who he said was totally supportive of the appointment.

He told the Queen, who has to sign off the appointment, two weeks ago.

"She was thrilled."

Mr Key said Lt Gen Mateparae would be knighted.

"He's just a warm, engaging New Zealander," he said.

"He will bring great mana and a wide range of abilities to the role."

"Jerry has served New Zealand with dedication and honour throughout his career."

Lt Gen Mateparae is currently the director of the Government Communications Security Bureau.

Mr Key said Lt Gen Mateparae he would continue in that role until June.

"We sought advice on that. Jerry will be stepping down in June ... the advice from the State Services Commission is that would be appropriate.

"There's no inherent conflict there ... at the end of the day he has served 38 years in the military in an apolitical way."

In an earlier statement, Mr Key said Lt Gen Mateparae was "a highly regarded leader with a distinguished 38-year military career".

He said Lt Gen Mateparae had joined New Zealand Army in 1972 and risen through the ranks, serving and commanding.

"Jerry has served New Zealand with dedication and honour throughout his career, and I am delighted that he has agreed to continue that service in a new, broader role," Mr Key said.

"I believe he will bring great mana and a wide range of qualities to this role, including judgement, energy and an enthusiasm for encouraging excellence in others."

There will be a State farewell for Sir Anand on 17 August. Mr Key thanked him for his dedication and service.

Lt Gen Mateparae's background

Mr Mateparae was born in Wanganui in 1954 and is affiliated to Ngati Tuwharetoa and Ngati Kahungunu.

He is married with two daughters and three sons and his activities include supporting the Rotary Club of Wellington and serving as patron to the New Zealand Special Air Service Association.

His military career saw him serve with the New Zealand Infantry Regiment and the elite SAS force before moving into leadership roles in Lebanon and East Timor.

That culminated with his appointment as Chief of Defence in 2006. He was the first Maori person to hold the position.

Mr Mateparae left that role in late 2010 to begin a five-year posting as director of the Government Communications Security Bureau.

He has worked just one month of that appointment.

A poll released by the Republican Movement last month saw Mr Mateparae emerge as the top choice for next Governor-General, with 34 per cent of the vote.

Next on the list was scientist, inventor and entrepreneur Ray Avery, with 16 per cent.